concurrent_context.js

const Thread = Java.type('java.lang.Thread')
// `function run()` is converted to a Java Runnable instance by GraalVM
const t = new Thread(function run() {
    // this will never be executed, as an exception will be thrown
    console.log('hello from another thread!')
});
// creating a thread does not imply concurrent access to a shared JS object.
// starting the thread, however, will result in a concurrent access to the
// shared Runnable object (that is, the JavaScript 'run' function above).
t.start();
// An IllegalStateException will be thrown as soon as the new thread starts.
t.join();